Multifocal electroretinographic changes in patients receiving hydroxychloroquine therapy

PURPOSE: To evaluate the longitudinal changes in multifocal electroretinography (mfERG) in patients receiving hydroxychloroquine and to assess the effects of cumulative hydroxychloroquine dose on mfERG. DESIGN: Prospective cohort study. METHODS: Twenty-four eyes in 12 patients receiving hydroxychloroquine underwent mfERG recordings at baseline and 1 to 2 years later. The first negative (N1) and first positive (P1) response amplitudes and peak latencies were compared with normal controls. Serial changes in the pattern of mfERG abnormalities and in response amplitudes and peak latencies were also compared between eyes in which hydroxychloroquine therapy was continued or stopped. Correlation analyses were performed to assess the effects of a cumulative dose of hydroxychloroquine on mfERG. RESULTS: At baseline, reductions in N1 and P1 response amplitudes were observed in patients receiving hydroxychloroquine compared with controls. At follow-up, in addition to the reductions in N1 and P1 response amplitudes, increases in P1 peak latencies compared with controls were observed. In patients who stopped hydroxychloroquine therapy, there were significant increases in N1 and P1 response amplitudes at follow-up mfERG. CONCLUSIONS: Patients receiving hydroxychloroquine showed a longitudinal decline in retinal function; patients who stopped hydroxychloroquine therapy showed improvement. Although these data are insufficient to demonstrate the sensitivity of mfERG for evaluating early hydroxychloroquine toxicity, the results suggest that serial mfERG assessment may help detect early retinal changes associated with hydroxychloroquine therapy. Further studies with long-term results will be useful in clarifying the value of mfERG in evaluating early retinal toxicity due to hydroxychloroquine.     

Retinal disorders in northern Brazilian patients treated with chloroquine assessed by multifocal ERG

The effects of chloroquine intake on the retinal function in a Brazilian population of patients were assessed by multifocal electroretinography. Twenty-four randomly chosen eyes of patients treated with chloroquine for rheumatoid arthritis and systemic lupus erythematosus were examined using multifocal electroretinography (mfERG). Control measurements were acquired from 21 randomly chosen eyes of age-matched healthy subjects. None of the study participants had an inherited retinal disease or a Snellen visual acuity reduced to less than 20/40. In patients and control subjects, cumulative chloroquine dose, total daily dose, duration of treatment, retinal examination, visual field defects, visual acuity, and the mfERG were assessed. The average amplitudes and implicit times of the N1, P1, and P2 components of the mfERGs were measured in the central hexagon (R1) and in five rings (R2–R6). The values measured in patients and normal subjects were compared. The P1 amplitudes in R2 were significantly decreased in the patients. In addition, the amplitudes of N1 and N2 in R1 were significantly smaller in the patients. The implicit times of none of the components were significantly different between patients and controls. The response amplitude was not significantly correlated with cumulative dose and duration of intake. There was no correlation with retinal appearance, visual field, and visual acuity. In agreement with earlier data, the central mfERG amplitudes were decreased in chloroquine patients indicating functional alterations in the retina. These changes are also present in a Brazilian population suggesting that the effects of chloroquine are general and that genetic background and life circumstances probably have, if at all, only little effect.     

Correlation between functional and anatomical assessments by multifocal electroretinography and optical coherence tomography in central serous chorioretinopathy

To evaluate the correlation between functional and anatomical assessments with multifocal electroretinography (mfERG) and optical coherence tomography (OCT) in patients with acute central serous chorioretinopathy (CSC). Thirty-four eyes of 34 patients with acute CSC underwent mfERG and OCT examinations. First-order mfERG N1 and P1 response amplitudes and latencies were analyzed. OCT parameters measured included central subretinal fluid (SRF) thickness, central retinal thickness, total central foveal thickness, vertical, and horizontal diameters of SRF, and macular volume. Correlation analyses were performed between best-corrected visual acuity (BCVA), mfERG parameters, and OCT measurements. Correlation analysis showed that logMAR BCVA was significantly correlated with mfERG N1 amplitudes of rings 1 and 2 (P = 0.006), N1 latency of ring 4 (P = 0.012), and P1 latency of ring 1 (P = 0.036). No significant correlation was observed between logMAR BCVA and any of the OCT measurements. For the correlation between mfERG parameters and OCT measurements, mfERG N1 and P1 latencies of the paracentral rings were significantly correlated with the central SRF thickness (P ≤ 0.024), diameters of the SRF (P ≤ 0.018), and macular volume (P ≤ 0.030). MfERG responses but not OCT measurements correlated with logMAR BCVA in patients with acute CSC. The amount of SRF nonetheless correlated with the mfERG N1 and P1 latencies of the paracentral rings, suggesting that impairment in the conduction of electrical responses in the paracentral macula is proportional to the severity of serous macular detachment in CSC. MfERG and OCT can complement each other in the functional and anatomical assessments in CSC.     

30 Hz-flicker mfERG in primary open-angle glaucoma patients

Purpose This study was performed in an attempt to gain more information on whether the 30 Hz-flicker mfERG indeed provides a sensitive measure of dysfunction in patients with primary open-angle glaucoma (POAG) as has been suggested previously.Methods Eighteen POAG patients with visual field defects (MD > 2.2 dB) and glaucomatous optic neuropathies as well as 10 control subjects underwent mfERG recording as follows: 30 Hz-flicker mfERG, LED stimulus screen, 61 hexagons, L _max: 180 cd/m², L _min: 0 cd/m², recording time: ∼5 min, filter setting: 10–200 Hz. The 30 Hz response (also called the fundamental or the first harmonic response (1HW) and the second harmonic wave at 60 Hz (2HW) were analysed as an overall response and in quadrants, as well as in 4 small neighbouring areas per quadrant. The patients’ mfERGs were compared to those of the control group and to the mean defect values (MD) of the corresponding quadrants of the Octopus perimetry.Results Neither in the overall response, nor in the quadrants, nor in the smaller areas examined did amplitudes and phases of the 1HW and the 2HW or the amplitude ratio of the 2HW to the 1HW (DFT-ratio) differ from the controls (P > 0.05—ANOVA). There was no significant correlation between mfERG values and the MD (Spearman-test, Bonferroni).Conclusion Thus, the 30 Hz-flicker mfERG does not seem to be sensitive enough to separate glaucoma patients from normal.     

Detection of early hydroxychloroquine retinal toxicity enhanced by ring ratio analysis of multifocal electroretinography

PURPOSE: To assess decreased retinal function associated with high cumulative doses of hydroxychloroquine using multifocal electroretinography (mfERG). DESIGN: Retrospective cross-sectional study. METHODS: Sixty-two patients referred for evaluation of hydroxychloroquine retinal toxicity. Controls were 67 normal eyes of 67 patients referred for a variety of conditions in the other eye. Visual symptoms, duration of treatment, daily hydroxychloroquine dose (milligrams and milligrams per kilogram), cumulative dose, condition for which the drug was taken, visual acuity, retinal examination, visual fields, and mfERG amplitude. The average mfERG amplitude was calculated for five concentric rings. The age-corrected amplitude of the central hexagon (R(1)) and the ratios of R(1) to each of the other rings (e.g., R(1)/R(2), R(1)/R(3)) were compared with limits derived from control eyes. RESULTS: The incidence of characteristic mfERG abnormalities in patients referred for evaluation with cumulative hydroxychloroquine doses of more than 1250 g was nearly 50%. It was 2.8 times that found in patients with cumulative doses less than 1250 g. Significant abnormalities were seen with cumulative doses as low as 400 g. The mfERG abnormality most commonly detected was an increased R(1)/R(2) ratio. Cumulative dose was more predictive of mfERG abnormalities than daily dose (either in milligrams or milligrams per kilogram) or duration of treatment. CONCLUSIONS: Functional testing of the retina with mfERG shows locally decreased retinal function in a large fraction of patients referred for evaluation who have taken high cumulative doses of hydroxychloroquine. A prudent mfERG testing strategy is proposed.     

First and second-order kernel multifocal electroretinography abnormalities in acute central serous chorioretinopathy

Purpose To evaluate the first and second-order kernel multifocal electroretinogram (mfERG) response abnormalities in patients with acute central serous chorioretinopathy (CSC). Methods This was a cross-sectional observational study in which 45 eyes of 45 patients with acute CSC underwent mfERG recordings. Peak amplitudes and implicit times of the first and second-order kernel responses were analyzed and compared with 20 age-matched normal controls. Correlation analyses were performed between the patients’ visual acuity and the first and second-order amplitudes and implicit times. Results The first-order N1 and P1 mfERG amplitudes in the central three concentric rings were reduced in eyes with acute CSC compared with controls (P < 0.05). The first-order P1 implicit times of the central four rings were also delayed (P < 0.05). For the second-order mfERG response, there were significant reductions in the second-order P1 and N1 amplitudes in rings 3–5 compared with controls (P < 0.05). No significant difference between the second-order P1 and N1 implicit times was found compared with controls (P > 0.05). Correlation analyses showed significant correlations between visual acuity and the first-order N1 response amplitudes of rings 1 and 2, and for the first-order N1 and P1 implicit times of rings 1–4 (P < 0.05). Conclusion Both first and second-order mfERG response abnormalities occur in eyes with acute CSC. These results suggest that in acute CSC, while outer retinal dysfunction is mostly localized to the central macula, there might be more widespread impairment in adaptive mechanisms of the inner retina or outer plexiform layer dysfunction in the more peripheral macula. Presented in part in the 44th annual symposium of the International Society of Clinical Electrophysiology of Vision (ISCEV), Fontevraud, France, June 2006.     

In diabetic retinopathy, foveal thickness of 300 μm seems to correlate with functionally significant loss of vision

Purpose To study the relationship between foveal thickness assessed by optical coherence tomography (OCT) and foveal function measured with multi focal electroretinography (mfERG) in patients with non-proliferative diabetic retinopathy, and with no previous laser treatment. Methods Twenty-six eyes from 18 diabetic patients (13 men), aged 59 years, (range 28–79 years), diabetes duration 15 years, (range 2–27 years), with a macular thickness between 200 and 600 μm were evaluated by mfERG, visual acuity (ETDRS score) and OCT. Mean amplitudes and implicit times of the mfERG responses were analyzed within the four innermost (14 degrees) of the six concentric rings. For comparison with the results from the OCT (diameter of measured area = 6 mm) we analyzed the summed response from the first and second ring (central zone), corresponding to the central area of the OCT. The third(zone 2) and fourth (zone 3)of the four innermost of the six concentric rings measured by the mfERG corresponding to the second and third area of OCT. Results An increased macular thickness in the central area of the OCT correlated to reduced amplitudes (r = −0.541; P = 0.004) and prolonged implicit times (r = 0.548; P = 0.004) in the central zone of the mfERG, and inversely correlated with visual acuity, −0.49; P = 0.045. Retinal thickness in the second area was correlated to prolonged implicit times in the second mfERG zone (r = −0.416; P = 0.034). No correlations were found for the third area of the OCT. When macular thickness exceeded 300 μm the decrease of amplitudes and prolonged implicit times, measured by mfERG, seemed to be more pronounced. Conclusion In conclusion increased macular thickness is correlated with reduced amplitudes and prolonged implicit times on the mf ERG and worse visual acuity.     

特发性视网膜前膜患者的多焦视网膜电图改变

目的:应用多焦视网膜电图(multifocalelectroretinogram,mfERG)对正常对照眼和特发性视网膜前膜眼进行检测并比较两者之间的差异。方法:用VERISScience4.0视诱发反应图像系统对17例(20只眼)正常对照者和15例(19只眼)特发性视网膜前膜患者进行检测。结果:特发性视网膜前膜患者皆出现程度不同多焦视网膜电图异常,与正常对照组的比较显示视网膜前膜组1～6环的P1波反应密度值和1～6环的N1波潜伏期与正常对照组有显著性差异,视力与第一环振幅无相关但与第一环的潜伏期存在相关。结论:多焦视网膜电图可用于对特发性视网膜前膜患者进行视功能评估。     

应用OCTA检测羟氯喹对系统性红斑狼疮患者黄斑区视网膜微血管形态的影响

目的　通过光学相干断层扫描血管成像（optical coherence tomography angiography,OCTA）检测羟氯喹（hydroxychloroquine,HCQ）对系统性红斑狼疮（systemic lupus erythematosus，SLE)患者黄斑区视网膜微血管形态的影响。方法　回顾性病例研究。将服用HCQ的患者60例60眼纳入研究，根据HCQ视网膜毒性的服药累积时间，将患者分为高危组（服药累积时间≥5 a）和低危组（服药累积时间<5 a），所有患者均进行光学相干断层扫描（optical coherence tomography,OCT）、OCTA、自动化视野检查（auto visual field,AVF）及多焦视网膜电图（multifocal electroretinography,mfERG）检查。结果　与低危组相比，高危组患者OCTA检查结果显示，视网膜浅表毛细血管丛和深部毛细血管丛血管密度均降低（均为P<0.05），而中心凹无血管区扩大（P<0.05）。 HCQ累积剂量和累积时间均与FAZ参数呈正相关（均为P<0.05）。在视野测试中，与低危组相比，高危组的平均偏差增加。在mfERG检查中，高危组的中心凹及旁中心凹振幅密度较低危组均有下降（均为P<0.05）。结论　OCTA通过评估视网膜微血管变化有助于检测HCQ引起的视网膜毒性。     

Comparing the multifocal electroretinogram topography before and after cataract surgery

PURPOSE: To investigate whether multifocal electroretinogram (mfERG) topography would be affected by nuclear cataract. METHODS: Multifocal electroretinograms were recorded from 10 elderly subjects (10 eyes) with nuclear cataract of grade five (LOCS III) before and after cataract surgery (phacoemulsification). Their visual acuity before the cataract surgery was between 6/12 and 6/18. The postoperative period was from 2 to 3 months. None of the subjects had any significant eye disease apart from cataract. The mfERG responses were grouped into six concentric rings for analysis. Both the amplitudes and the latencies of N1 and P1 of first-order responses were used for analysis. RESULTS: N1 amplitude only from ring 1 increased significantly after cataract surgery. P1 amplitude from ring 1 and ring 2 also increased significantly after cataract surgery. The latencies of neither N1 nor P1 from all rings changed significantly. CONCLUSIONS: Nuclear cataract could affect the topography of mfERG, so clinicians should be aware of the effects of cataract when interpreting mfERG responses in cataract patients.     

Assessment of retinal function in patients with HIV without infectious retinitis by multifocal electroretinogram and automated perimetry

PURPOSE: To determine if multifocal electroretinogram (mfERG) testing shows abnormalities that correspond to perimetric defects in HIV positive patients without infectious retinitis. METHODS: We studied three groups of patients: HIV negative controls, HIV high CD4 nadir patients (lowest CD4 T cell count is over 100) and low CD4 nadir patients (below 100 for over 6 months). Twenty-six HIV positive eyes and 16 HIV negative control eyes were studied by mfERG. A subset of 10 eyes also underwent computerized perimetry for comparison. We analyzed mfERG by hexagons as well as by quadrants and rings. RESULTS: Of 103 hexagon locations there was no significant difference in the amplitudes P1 and N1 (nV/degree) between the three studied groups (p>0.05), similarly, the latencies were not different (p>0.05). All eyes with significant visual field defects at the 0.01 and 0.005 level (Humphrey pattern deviation; 24-2) were compared to mfERG amplitudes and latencies at those locations-there were no corresponding defects in mfERG data (p>0.2). CONCLUSION: In the era of HAART there are still demonstrable visual field defects and other evidence of damage to the retinal nerve fiber layer in HIV patients. Our mfERG studies show that the damage appears to affect the inner retina, the outer retina is spared. Further studies of inner retinal structure and function are indicated to elucidate this process.     

Assessment of macular function by multifocal electroretinography following epiretinal membrane surgery with indocyanine green-assisted internal limiting membrane peeling

Purpose To evaluate the changes in macular function and potential retinal toxicity in epiretinal membrane (ERM) surgery with indocyanine green (ICG)-assisted internal limiting membrane (ILM) peeling using multifocal electroretinography (mfERG).Methods Thirteen eyes of 13 patients were randomly assigned to have ERM surgery with ILM peeling using 0.5 mg/ml or 1.25 mg/ml ICG staining. Patients were examined at baseline and at 3 and 6 months postoperatively. The postoperative mfERG N1 and P1 response amplitudes and peak latencies of various ring eccentricities were assessed and compared with baseline to determine any serial changes.Results After surgery, the median best-corrected visual acuity improved from 20/70 at baseline to 20/30 at 6 months postoperatively (Wilcoxon signed-ranks test, P=0.004). At 3 months postoperatively, the 0.5 mg/ml group showed no significant changes in N1 and P1 response amplitudes and peak latencies, whereas the 1.25 mg/ml ICG group showed significant reductions in N1 and P1 response amplitudes compared with baseline. No significant changes in mfERG responses were observed in either group at 6 months after surgery.Conclusions Our mfERG findings suggested that the use of a higher concentration of ICG for ILM staining might result in transient retinal functional impairment postoperatively. The lowest possible concentration of ICG should be used intraoperatively to minimize potential retinal toxicity.     

复杂性视网膜脱离的多焦视网膜电图研究

目的 探讨多焦视网膜电图（mfERG）对复杂性视网膜脱离（RD）视功能客观评价的意义。方法 应用VERIS ScienceTM 4．2mfERG检测仪对80例复杂性RD患者的双眼进行检测,并与正常对照组比较。结果 复杂性RD患者的对侧眼、患眼在6个环的N1波、P1波振幅密度较正常对照组降低,潜时延长,差异均有统计学意义（P〈0．01）。有严重玻璃体积血组的N1、P1波振幅密度在2～6环高于无严重玻璃体积血组,差异均有统计学意义（P〈0．05）。重度PVR组的N1、P1波振幅密度低于轻度PVR组,在6个环差异均有统计学意义（P〈0．05）。黄斑裂孔组在所有6个环的N1、P1波振幅密度较正常对照组降低,潜时延长,差异均有统计学意义（P〈0．01）。结论 mfERG能客观定量评价复杂性RD患者的视功能。严重的玻璃体积血、黄斑裂孔、PVR对视功能有明显影响。     

中心性浆液性脉络膜视网膜病变OCT与mfERG图像的相关性

目的利用光学相干断层扫描（OCT）与多焦视网膜电图（mfERG）分析中心性浆液性脉络膜视网膜病变（csc）患者的OCT与mfERG图像的关系。方法横断面研究。应用德国CarlZeissCirrusHD-OCT及美国EDI VERIS Science^TM4．9视诱发反应图像系统对40只急性期CSC眼（40例）进行检查。将CSC患者OCT黄斑厚度图三个环的视网膜平均厚度与相对应的多焦视网膜电图（mfERG）的1＋2环、3环、4环的N1、P1波的平均反应密度和峰时间进行比较,并将黄斑区体积、总的黄斑中心凹的厚度、视网膜下液高度、视网膜下液范围和中心凹神经上皮厚度与mfERG6个环的N1、P1波反应密度和潜伏期比较分析。采用Spearman秩相关进行数据分析。结果CSC患者OCT内环、中环、外环的视网膜平均厚度与mfERG1＋2环、3环、4环的N1、P1波的峰时间呈正相关。黄斑区体积、总的黄斑中心凹的厚度、视网膜下液高度和视网膜下液范围与mfERG的N1、P1波反应密度和峰时间有显著的相关性。结论CSC患者的黄斑平均视网膜厚度及积液情况与mfERG之间有一定的相关性,可用OCT测量黄斑区视网膜下液的积液量,尤其是用积液范围来评估黄斑区视网膜功能的改变。OCT与mfERG的检测可以综合评价CSC患者的形态与功能的变化。     

Transitions of multifocal electroretinography following combined intravitreal bevacizumab and photodynamic therapy for polypoidal choroidal vasculopathy

Multifocal ERG ring ratios provide a sensitive and objective method to detect ocular toxicity in patients taking hydroxychloroquine (Plaquenil). In order to measure ring ratios, the average mfERG amplitude was calculated for each of five concentric rings of a 61-hexagon mfERG. The age-corrected amplitude of the central hexagon (R₁) and the ratios of R₁ to each of the successive rings (R₁/R₂, R₁/R₃, etc.) were then computed. Normative values for ring ratios were established from a population of 67 normal controls. In the study population, a ring was considered abnormal if it was above the 99% confidence limits for the normal population. The technique was evaluated on 131 eyes of 62 patients taking Plaquenil for a variety of conditions including rheumatoid arthritis, systemic lupus erythematosus, and Sjögren’s syndrome. Patients who had taken Plaquenil for an extended period showed a higher incidence of retinal toxicity, regardless of the condition for which they were taking the drug. Among patients who had taken a cumulative dose of less than 1,250 g, 7 of 67 eyes (10%) showed a characteristic mfERG defect, while in patients with a cumulative dosage of 1,250 g or more, 26 of 64 eyes (41%) showed one of these defects. In at least one patient, the technique was able to detect the early onset of Plaquenil toxicity followed by reversal of the toxic effects after the medication was discontinued. It appears appropriate to recommend that mfERG testing be done on all patients on Plaquenil therapy.     

Follow up in open angle glaucoma. A comparison of static perimetry and the fast stimulation mfERG

PURPOSE: To compare changes in the mfERG to visual field changes observed in OAG. METHODS: Twenty-nine eyes with OAG were included. Visual fields (Octopus d32) and mfERGs (VERIS) were obtained at a mean interval of 9 months (SD 6 months). MfERG recording parameters were as follows: 103 hexagons stimulated the central 50 degrees. M-sequence 2--5, stimulus base interval 13.33 ms, Lmax 200 cd/m2, contrast 99%. First (KI) and second (KII) order response components were analyzed for the individual quadrants of the visual field and compared to the corresponding mean deviation (MD) of the static perimetry. RESULTS: Changes in visual field parameters and changes in the mfERG did not differ significantly. Overall, as mean deviation increased there was a tendency for implicit times to increase and for amplitudes to decrease. However, over the follow up interval of 9 months only minor changes were observed. The second order response component correlated best with changes in MD (p < 0.05). These were the correlation between MD and KII N1 (r: 0.36) in the upper temporal field, between MD and KII N2 (r: 0.40) in the upper nasal field and between MD and KII P1 (r: 0.38) in the lower temporal field. When a subgroup of 10 eyes that had been tested at least 3 times over 16.8 months (SD 5.5) was examined there were still only minor changes observed in either parameter. CONCLUSION: While the changes over time in the mfERG and the visual field showed a reasonable correlation, changes observed in either parameter were extremely small over the time period observed, thus requiring a longer follow up and/or a more sensitive stimulation technique.     

Transient reduction in retinal function revealed by multifocal electroretinogram after photodynamic therapy

PURPOSE: To evaluate the early changes in retinal function after photodynamic therapy (PDT) by multifocal electroretinogram (mfERG). DESIGN: Prospective interventional case series. METHODS: Seventeen eyes from 17 patients scheduled for standard PDT with verteporfin were prospectively recruited. Patients' diagnoses included choroidal neovascularization (CNV) secondary to age-related macular degeneration, idiopathic CNV, myopic CNV, polypoidal choroidal vasculopathy, and central serous chorioretinopathy. Serial mfERG recordings were performed before PDT, and at 4 days, 2 weeks, and 1 month after PDT. The first-order kernel N1 and P1 mfERG response from the central 0 to 7 degrees and peripheral 7 to 25 degrees were grouped and analyzed. The mean response amplitudes and peak latencies of the mfERG recordings were compared longitudinally. RESULTS: There were statistically significant reductions in the mean N1 response amplitude for the central group at 4 days (P =.007) and 2 weeks after PDT (P =.024), in the mean P1 response amplitude for both the central (P =.006) and peripheral (P =.013) groups at 4 days, and for the central group at 2 weeks after PDT (P =.017). There were also statistically significant increases in the mean P1 response latencies at 4 days (P =.004) and at 2 weeks (P =.018) after PDT for the central group and at 4 days after PDT (P =.026) for the peripheral group. At 1 month after PDT, no significant differences in the N1 and P1 mean response amplitudes and peak latencies were observed compared with pre-PDT mfERG. CONCLUSIONS: Transient impairments in retinal function for as long as 2 weeks after PDT were noticed by reduction in response amplitudes and a delay in peak latencies of mfERG. These findings may explain the common adverse event of subjective visual disturbance early after PDT with normal findings in visual acuity and ophthalmoscopy.     

Macular function by multifocal electroretinogram in diabetic macular edema after intravitreal triamcinolone acetonide injection

PURPOSE: The purpose of this study was to assess macular function by multifocal electroretinography (mfERG) in eyes with diabetic macular edema (DME) after intravitreal triamcinolone acetonide (IVTA) injection. METHODS: Fifteen eyes of 15 patients with DME scheduled for 4 mg IVTA injection were prospectively recruited. The response to treatment was monitored functionally by visual acuity (VA) measurement and mfERG and anatomically by foveal thickness measured by optical coherence tomography (OCT). The first-order kernel P1 mfERG responses from 0 to 7 degrees (central) and 7 to 25 degrees (peripheral) were grouped and analyzed. Changes in functional parameters (VAs and the P1 mfERG response amplitudes and peak latencies) and morphometric parameters (OCT foveal thickness) in eyes with DME 1 and 3 months after IVTA injection were compared with baseline values by Student t test. RESULTS: The mean baseline logMAR value for VAs of the patients before treatment was 0.49+/-0.26. After treatment, it was 0.27+/-0.23 at 1 month and 0.26+/-0.18 at 3 months, and differences from pretreatment values were significant (for each, p<0.001). There were statistically significant decreases in the mean foveal thickness at 1 and 3 months after treatment compared with pretreatment values (for each, p<0.001). There were also statistically significant increases in the mean P1 response amplitude for both central and peripheral groups at all examinations compared with pretreatment (for each, p<0.001). The mean P1 peak latencies for both the central and peripheral groups were shortened, but not significantly. CONCLUSIONS: As well as the reduction in DME and improvement in VA, IVTA injection improves macular function as assessed by mfERG in diabetic patients.     

Global flash multifocal electroretinogram: early detection of local functional changes and its correlations with optical coherence tomography and visual field tests in diabetic eyes

Purpose To investigate the correlations of the global flash multifocal electroretinogram (MOFO mfERG) with common clinical visual assessments—Humphrey perimetry and Stratus circumpapillary retinal nerve fiber layer (RNFL) thickness measurement in type II diabetic patients. Methods Forty-two diabetic patients participated in the study: Ten were free from diabetic retinopathy (DR), while the remainder suffered from mild to moderate nonproliferative diabetic retinopathy. Fourteen age-matched controls were recruited for comparison. MOFO mfERG measurements were made under high- and low-contrast conditions. Humphrey central 30-2 perimetry and Stratus OCT circumpapillary RNFL thickness measurements were also performed. Correlations between local values of implicit time and amplitude of the mfERG components [direct component (DC) and induced component (IC)], and perimetric sensitivity and RNFL thickness were evaluated by mapping the localized responses for the three subject groups. Results MOFO mfERG was superior to perimetry and RNFL assessments in showing differences between the diabetic groups (with and without DR) and the controls. All the MOFO mfERG amplitudes (except IC amplitude at high contrast) correlated better with perimetry findings (Pearson’s r ranged from 0.23 to 0.36, p < 0.01) than did the mfERG implicit time at both high and low contrasts across all subject groups. No consistent correlation was found between the mfERG and RNFL assessments for any group or contrast conditions. The responses of the local MOFO mfERG correlated with local perimetric sensitivity but not with RNFL thickness. Conclusion Early functional changes in the diabetic retina seem to occur before morphological changes in the RNFL.     

Macular function assessed with mfERG before and after panretinal photocoagulation in patients with proliferative diabetic retinopathy

Purpose: To examine macular function and its correlation to macular thickness before and after panretinal photocoagulation for proliferative retinopathy in diabetic patients. Methods: Ten diabetic patients (aged 57 ± 10 years, diabetes duration 21 ± 10 years) treated with panretinal photocoagulation outside the great vascular arcade underwent multifocal electroretinography (mfERG) and optical coherence tomography (OCT) before and 6 months after treatment. When focal treatment in the macular region was performed prior to panretinal photocoagulation the investigations took place 3 weeks after this treatment but before the panretinal photocoagulation. One eye per patient was examined. Amplitudes and implicit times of the mfERG response were analyzed within the four innermost (27°) of the six concentric rings registered by the mfERG, which corresponds to the area measured by the OCT (Ø 3.5 mm). Results: Visual acuity was similar before and after photocoagulation, 1.0; 0.7–1.0 (md, range) versus 1.0; 0.6–1.0 (md, range). The mean values of the ring average amplitudes were reduced in the first and second, third and fourth concentric rings from foveola after photocoagulation, p= 0.001, p= 0.011 and p= 0.004, respectively. No change was seen in implicit time after treatment. OCT values were similar before and after photocoagulation. There was no correlation between retinal thickness assessed with OCT and amplitudes measured by the mfERG. Conclusion: In spite of unchanged values of retinal thickness and visual acuity, panretinal photocoagulation seems to cause a functional impairment in the adjacent untreated macula, shown by reduced amplitudes measured by the mfERG.